public class Main {
	public static void main(String[] args) {
		final char start = 'A', mid = 'C';

		for (int row = start; row <= mid; ++row) {
			for (int format = 0; format < (mid - row); ++format) System.out.print(" ");
			for (char left = start; left <= row; ++left) System.out.print(left);
			for (char right = (char) (row - 1); right >= start; --right) System.out.print(right);
			System.out.println();
		}
	}
}